In daily life, there are some electronic products with a camera, such as various computers, cell phones, and so on. No protection device is provided for the camera of these electronic products. When frequently exchanging data mutually through mobile memory devices, our electronic products may probably be infected with trojan-horse viruses. Or, on the internet, some people intendedly distribute some trojan-horse viruses. Therefore, after someone takes control of the computer by means of the Trojan-horse virus, he may perform illegal activities such as surreptitious photo-taking, thus impairing the user's rights and causing the psychological damage to the user.